1. Field of the Invention
The present invention relates to a hex wrench that includes a driving end for high torque operation.
2. Description of the Related Art
A typical hex wrench is substantially L-shaped and includes a longer section and a shorter section. FIG. 9 of the drawings illustrates a hex wrench 1 that has an end engaged in a counterbore 3 of a screw head 2. The hex wrench 1 has a relatively long contact length "X" with the counterbore 3 to allow high-torque operation. Nevertheless, in some cases, the screw to be driven is located in a limited space that is difficult to access. The hex wrench usually has to be operated in a slanted manner. Referring to FIGS. 10 and 11, a hex wrench 4 with a ball-like driving end 5 formed on a longer section thereof is proposed to allow the driving end 5 to be received in the counterbore 3 of the screw head 2 in either a slanted manner or an upright manner. It is, however, found that the effective contact length between the driving end 5 and the screw head 2 is reduced to "B", which is much smaller than "X". As a result, high-torque operation cannot be provided. If the driving end 5 is formed on the shorter section of the hex wrench, it cannot be used in a limited space. Thus, the users has to carry two sets of hex wrenches: one set of normal hex wrenches for high-torque operation, and the other set of hex wrenches with ball-like driving ends for use in limited space, yet the use and carriage are both inconvenient. The present invention is intended to provide an improved hex wrench to solve these problems.